So basically in recent history - which is to say, I being American and therefore somewhat self-centered, the past 250 years or so - we have three major times where it looked like some nation, at least to the majority of the population, might come to Rule the World, or at least establish a strong hegemony over it (say, of the sort that America enjoyed throughout the 90s and 00s, or the Pax Britannica): The USSR; Nazi Germany; and Napoleonic France.
Now, the USSR certainly had all the ingredients, the population, the industry, etc., it just had a number of organizational issues. But the Cold War was fought for a reason: it definitely had a chance of winning, however slim.
We now know, of course, that Nazi Germany never had much of a chance of actually winning WWII. Apparently it's doubtful that it could have beaten Britain alone, let alone Britain, America, and the Soviet Union combined. It put on a good show and had some really impressive gains, but ultimately it was always running on a time limit, and even if it had taken down Britain, there was a certain Red menace that it was never going to defeat.
But what about Napoleon? I'm not entirely certain what his end-goals were. But how close was he to achieving them? Could France really have come out the other side of his rule as the dominant world power if he had done things a little differently? Things worked slightly more in his favor? Specifically here I'm wondering if it's possible with a POD of no earlier than 1799, when he seized power in France.